Boiler types: combi, system, regular, electric and oil
Most UK homes have a gas combi, system or regular boiler, and homes off the gas grid have an electric or oil one. Here is how each type works, who it suits and what it costs fitted.
- Gas combi boilersA gas combi boiler heats the radiators and makes hot water on demand from the mains, so there is no hot water cylinder and no header tank in the loft.from £1,800typically £2,70024 to 30kW gas combi boiler, like-for-like swap, fitted
- System boilersA system boiler heats the radiators directly and stores hot water in a cylinder.from £2,500typically £3,000Gas system boiler, like-for-like swap, fitted, hot water cylinder not included
- Regular boilersA regular boiler, also called a heat-only or conventional boiler, works with a hot water cylinder and a feed-and-expansion tank in the loft.from £2,500typically £3,000Gas regular (heat-only) boiler, like-for-like swap, fitted
- Electric boilersAn electric boiler heats the water with electric elements instead of burning gas, so it needs no flue and no gas supply.from £2,200typically £3,00012kW electric boiler, no cylinder, fitted
- Oil boilersAn oil boiler burns heating oil from a tank outside the house.from £2,700typically £3,300Oil boiler, heat-only at the low end and combi at the high end, fitted
How to choose a boiler type
Start with your hot water. A combi makes it on demand and needs no cylinder, so it suits one or two bathrooms. A system boiler stores hot water in a cylinder and suits a busy household. A regular boiler works with a cylinder and a loft tank and suits an older open-vented system. Electric and oil boilers are for homes with no gas.
Every type page shows what it typically costs fitted, what moves the price and what a quote should include, so you can compare like with like.
What to compare across boiler types
- Space. A combi needs only the wall space. A system boiler needs a cylinder, and a regular boiler needs a cylinder and a loft tank.
- Hot water. A combi runs one or two taps well. Stored hot water copes with several at once, and a system boiler is the usual way to get it.
- Fuel. Gas is cheapest to run where it is available. Oil and electric boilers are the answer where it is not, and both cost more to run.
- Cost. A like-for-like swap is the cheapest job. Our combi boiler prices page puts every model side by side.
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